Various shoulder injuries may result from dislocations and other injuries resulting from traumatic events such as falling or blunt force, or from repetitive motions such as throwing or lifting. A common shoulder injury includes the separation of the glenoid labrum from the glenoid. For example, a Bankart lesion results from a labrum tear that occurs in the anterioinferior region of the glenoid socket when the shoulder dislocates. A superior labrum anterior posterior (SLAP) lesion typically occurs from throwing injuries, where the tear occurs at the superior region of the glenoid socket where the biceps tendon attaches to the shoulder. These injuries result in pain and instability of the shoulder joints.
Arthroscopic stabilization for surgical treatment of shoulder instability has grown in popularity over the past decade. In particular, tissue anchors have been employed to repair torn labrum tissue. For example, a tissue anchor may be inserted into the glenoid, and a suture material that is attached to the anchor is used to reattach the torn labrum tissue to the glenoid.
Tissue anchors have similarly been used in other tissue repair procedures directed towards the rotator cuff, labrum tissue of the hip, and the like. Similar to the labrum repair above, such surgeries typically include placing a tissue anchor into bone at or adjacent to the site of tissue attachment (commonly at or adjacent to the native attachment site) and utilizing a suture to draw the tissue to be reattached towards the tissue anchor and thus, towards the bone. The suture is secured in a known fashion, such as by tying a knot, and the repair is complete.
Knotless tissue anchors have grown in popularity in recent years for use in these types of surgical procedures. Knotless tissue anchors, as commonly defined, do not require the tying of knots by an operator (e.g., surgeon) to secure the tissue to the bone. Instead, the anchor has another type of locking feature which secures the suture, and thus the tissue, without the tying of knots. Such anchors have grown in popularity due to their ease of use and simplification of the surgical procedure by, for example, eliminating the need for knot pusher instruments and the like.
However, currently used “knotless” tissue anchors typically still include a knot somewhere along the suture such that, even though the operator may not be required to tie a knot during the surgical procedure, the suture still includes a knot, typically pre-tied by the anchor manufacturer, along its length. This knot, over time and with repeated use, will tighten, thereby loosening the repair. In the example of a labrum repair, such tightening of the knot may loosen the repair such that the labrum is no longer positioned snugly against the bone surface. Such loosening may occur even if the suture remains intact.
Therefore, there is room for improvement over existing “knotless” anchors, particularly with regard to, for example, further simplification of insertion of such anchors, as well as better assurance of replication of the procedure. Additionally, there is a need in the art for a truly knotless tissue anchor which does not include any knots, whether pre-tied or tied by the operator, in the suture.